Abstract
Energy models have been developed for stereo depth perception in which the strength of stereo signal is proportional to the product of signal contrasts in the two eyes (Cormack et al, 1991). Although human subjects can see stereogram when considerable contrast difference exists between left and right eyes (Legge & Gu, 1989), how contrast gain-control functions in stereo depth perception has not been systematically investigated. Recently, we developed a multi-channel contrast gain-control model (MCM) for binocular phase and contrast perception (Huang et al, 2011; Huang et al, 2010) based on a contrast gain-control model of binocular phase combination (Ding & Sperling, 2006). In an attempt to extend the MCM to simultaneously account for stereo depth and cyclopean contrast perception, we systematically manipulated the contrasts of the dynamic random dots presented to the left and right eyes, and measured both the disparity threshold for depth perception and the perceived contrast of the cyclopean images. RDSs with all possible combinations of five contrasts, ranging from 0.08 to 0.4, were used in the experiment. We found that both disparity threshold and perceived contrast depended strongly on the signal contrasts in both eyes, exhibiting characteristic binocular contrast-gain control properties. The results were well accounted for by our extended MCM model, in which each eye exerts gain-control on the other eye’s signal in proportion to its own signal contrast energy, and also gain-controls over the other eye’s gain-control; stereo strength is proportional to the product of the signal strengths of the two eyes after contrast gain-control, and the perceived contrast is computed by combining contrast energy from the two eyes. The new model provided an excellent account of disparity thresholds and the perceived cyclopean contrasts with a single set of parameters (r2=0.92). It also accounted for some interesting results in the literature (Legge & Gu, 1989).
Meeting abstract presented at VSS 2012